The RV line of Selkirk round vent pipe and fittings is designed for use on approved gas appliances in residential and light commercial and industrial applications. Round vents for large appliances will be found in the QC section which follows. Size 4" Part No. 4RV-SC Measures: 1-916" x 7-58" Used to provide a weather proof seal to pipe above roof line Used above the Flashing Seal inner edge with hi-temp silicone sealant NOTE: See instructions for use/limitations